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The failure of once promising target-specific therapeutic strategies often arises from redundancies in gene expression pathways. Even with new melanoma treatments, many patients are not responsive or develop resistance, leading to disease progression in terms of growth and metastasis. We previously discovered that the transcription factors ETS1 and PAX3 drive melanoma growth and metastasis by promoting the expression of the MET receptor. Here, we find that there are multiple ETS family members expressed in melanoma and that these factors have redundant functions. The small molecule YK-4-279, initially developed to target the ETS gene–containing translocation product EWS-FLI1, significantly inhibited cellular growth, invasion, and ETS factor function in melanoma cell lines and a clinically relevant transgenic mouse model, BrafCA;Tyr-CreERT2;Ptenf/f. One of the antitumor effects of YK-4-279 in melanoma is achieved via interference of multiple ETS family members with PAX3 and the expression of the PAX3-ETS downstream gene MET. Expression of exogenous MET provided partial rescue of the effects of YK-4-279, further supporting that MET loss is a significant contributor to the antitumor effects of the drug. This is the first study identifying multiple overlapping functions of the ETS family promoting melanoma. In addition, targeting all factors, rather than individual members, demonstrated impactful deleterious consequences in melanoma progression. Given that multiple ETS factors are known to have oncogenic functions in other malignancies, these findings have a high therapeutic impact.Significance:These findings identify YK-4-279 as a promising therapeutic agent against melanoma by targeting multiple ETS family members and blocking their ability to act as transcription factors.

Supplementary figures S1, S2, and S3

Data are presented on the composition of identifiable molluscan shell debris from the surface of supralittoral strand-line accumulations from three topographically distinct coastal sites and aspects on the Isle of Cumbrae, Scotland sampled in summer and winter. Interpretation of these death assemblages, termed taphocoenoses, is given with reference to the biology and distribution of the same species living on- and off-shore and prevailing physical conditions at each site. Understanding such relationships allows the reconstruction of fossil deposits of dead shells, termed thanatocoenoses. The significance of dead-shell accumulations as carbon sinks has relevance to current modelling of climate change.

The failure of once promising target-specific therapeutic strategies often arises from redundancies in gene expression pathways. Even with new melanoma treatments, many patients are not responsive or develop resistance, leading to disease progression in terms of growth and metastasis. We previously discovered that the transcription factors ETS1 and PAX3 drive melanoma growth and metastasis by promoting the expression of the MET receptor. Here, we find that there are multiple ETS family members expressed in melanoma and that these factors have redundant functions. The small molecule YK-4-279, initially developed to target the ETS gene–containing translocation product EWS-FLI1, significantly inhibited cellular growth, invasion, and ETS factor function in melanoma cell lines and a clinically relevant transgenic mouse model, BrafCA;Tyr-CreERT2;Ptenf/f. One of the antitumor effects of YK-4-279 in melanoma is achieved via interference of multiple ETS family members with PAX3 and the expression of the PAX3-ETS downstream gene MET. Expression of exogenous MET provided partial rescue of the effects of YK-4-279, further supporting that MET loss is a significant contributor to the antitumor effects of the drug. This is the first study identifying multiple overlapping functions of the ETS family promoting melanoma. In addition, targeting all factors, rather than individual members, demonstrated impactful deleterious consequences in melanoma progression. Given that multiple ETS factors are known to have oncogenic functions in other malignancies, these findings have a high therapeutic impact. Significance: These findings identify YK-4-279 as a promising therapeutic agent against melanoma by targeting multiple ETS family members and blocking their ability to act as transcription factors.

Yes Associated Protein 1 (YAP) and Transcriptional coactivator with PDZ-Binding Motif (TAZ) are transcriptional coactivators that have been implicated in driving metastasis and progression in many cancers, mainly through their transcriptional regulation of downstream targets. Although YAP and TAZ have shown redundancy in many contexts, it is still unknown whether or not this is true in melanoma. Here we show that while both YAP and TAZ are expressed in a panel of melanoma cell lines, depletion of YAP results in decreased cell numbers, focal adhesions, and the ability to invade matrigel. Using non-biased RNA-sequencing analysis, we find that melanoma cells depleted of YAP, TAZ, or YAP/TAZ exhibit drastically different transcriptomes. We further uncover the ARP2/3 subunit ARPC5 as a specific target of YAP but not TAZ, and that ARPC5 is essential for YAP-dependent maintenance of melanoma cell focal adhesion numbers. Our findings suggest that in melanoma, YAP drives melanoma progression, survival, and invasion. SIGNIFICANCE: Our findings are the first to differentiate YAP from its ortholog TAZ as a unique driver of melanoma using cell dependency studies, non-biased RNA sequencing, and a downstream target-based approach. Genetic and functional data implicate the actin nucleating ARP2/3 complex in melanoma and we discovered that the ARP2/3 subunit ARPC5 is a downstream target of YAP but not TAZ. ARPC5 acts as a downstream effector factor for YAP in focal adhesion maintenance, likely contributing to melanoma migration and metastasis.

CREB controls ∼25% of the mammalian transcriptome. Small changes in binding to its consensus (CRE) sequence are likely to be amplified many fold in initiating transcription. Here we show that DNA lesions repaired by the base excision repair (BER) pathway modulate CREB binding to CRE. We generated Kd values by electrophoretic mobility shift assays using purified human CREB and a 39-mer double-stranded oligonucleotide containing modified or wild-type CRE. CRE contains two guanine residues per strand, one in a CpG islet. Alterations in CRE resulted in positive or negative changes in Kd over two orders of magnitude depending on location and modification. Cytosine methylation or oxidation of both guanines greatly diminished binding; a G/U mispair in the CpG context enhanced binding. Intermediates in the BER pathway at one G residue or the other resulted in reduced binding, depending on the specific location, while there was no change in binding when the single G residue outside of the CpG islet was oxidized. CREB recruits other partners after dimers form on DNA. Only UpG increased DNA.CREB dimer formation. Since oxidation is ongoing and conversion of cytosine to uracil occurs spontaneously or at specific times during differentiation and development, we propose that BER substrates are epigenetic and modulate transcription factor recognition/binding.

Having recently opted for early retirement (after more than 36 years coming up through the ranks as an academic at the University Marine Biological Station Millport (UMBSM) as Lecturer, Senior Lecturer, Reader, Professor and Acting Director) and thereby relinquished my status as the longest-serving

High resolution palaeoclimate data are required for the Holocene to resolve differences recorded by current proxies. The pole to pole distribution of rhodoliths (coralline algae) with their annual and sub-annual calcite bands make these attractive candidates for such a role. These bands contain climate information in the form of elemental traces. In situ temperature (IST) was recorded at two rhodolith beds for 1.5 years. The concentrations of MgCO 3 and SrCO 3 (mol %) deposited in Lithothamion glaciale and Phymatolithon calcareum over this 18- month period were determined using electron and ion microprobes. Highly significant linear relationships exist between Mg, Sr and IST as well as sea surface temperature. Calibration between Mg concentration and IST was used to obtain a 2-year temperature profile from a subfossil rhodolith thallus indicating half the seasonal peak-to-peak temperature amplitude earlier during the Holocene than the present day. Both slow-growing species ( −1 ) allowed sampling resolutions of 23 year −1 which is equivalent to 1 reading every 2 weeks. Sub-monthly Mg and Sr records in rhodoliths make them unique globally distributed palaeothermometers which may help refine regional climate histories during the Holocene.

Transcriptional regulation is a tightly regulated, vital process. The transcription factor cyclic AMP-response element-binding protein 1 (CREB1) controls ∼25% of the mammalian transcriptome by binding the CREB1 binding site consensus sequence (CRE) sequence (TGACGTCA). DNA lesions within CRE modulate CREB1 binding negatively and positively. Because appropriate DNA lesions also interact with base excision repair proteins, we investigated whether CREB1 and repair glycosylases compete with each other. We incubated 39-mer CRE-containing double-stranded oligonucleotides with recombinant CREB1 alone or with UNG2 or OGG1, followed by EMSA. The CpG islet within CRE was modified to contain a G/U or 8-oxoG (°G)/C mispair. OGG1 and CREB1 reversibly competed for CRE containing an °G/C pair. Also, OGG1 blocked CREB1 from dimerizing by 69%, even when total CREB1 binding was reduced only by 20-30%. In contrast, bound CREB1 completely prevented access to G/U-containing CRE by UNG2 and, therefore, to base excision repair, whereas UNG2 exposure prevented CREB1 binding. CREB1 dimerization was unaffected by UNG2 when CREB1 bound to CRE, but was greatly reduced by prior UNG2 exposure. To explore physiological relevance, we microinjected zebrafish embryos with the same oligonucleotides, as a sink for endogenous CREB1. As predicted, microinjection with unmodified or lesion-containing CRE, but not scrambled CRE or scrambled CRE with a G/U mispair, resulted in increased embryo death. However, only the G/U mispair in native CRE resulted in substantial developmental abnormalities, thus confirming the danger of unrepaired G/U mispairs in promoters. In summary, CREB1 and DNA glycosylases compete for damaged CRE in vitro and in vivo, thus blocking DNA repair and resulting in transcriptional misregulation leading to abnormal development.

A study was made of the efficiency of a commercially available hydraulic dredge design in use on the west coast of Scotland and of the annual biomass production of two different razor clam (Ensis spp.) beds within the Clyde Sea area. These two parameters, viz fishing efficiency and population annual production, are fundamentally important to any proper attempt to assess the long term sustainability of a fishery. The hydraulic dredge used in this study was found to have an absolute efficiency of 90.1% when expressed in terms of the collected wet weight biomass, representing the first time that the efficiency of a hydraulic dredge of this nature has been measured rather than simply inferred from track width. This indicates that this dredge design has the potential to remove the majority of a clam population, including undersized immature individuals, within a 45 cm swath in a single tow. Annual production estimates were also made for two separate razor clam beds. One population of Ensis siliqua was located in Irvine Bay and the other two populations (one E. siliqua and one E. arcuatus) occurred in a mixed bed on Hunterston Sands. Each location was sampled quantitatively on a regular basis using the same hydraulic dredge. Dredged areas were measured by SCUBA divers so that the population densities could be calculated for each sampling event. Size-classes within each population were identified from siphonal shell breadth measurements and production estimates were calculated using a size-cohort analysis procedure designed for stocks exhibiting recruitment but that do not have separable age-classes. Production of all three populations was low during the study (1.82–18.08 g AFDW 10 m-2) as were the production/biomass estimates (0.01–0.11). These data indicate that populations of Ensis spp. on the west coast of Scotland are slow-growing and typical of K-selected species. These data highlight the conflicting pressures facing any razor clam fishery: the design of extremely efficient hydraulic gear and the slow-growth of the target species. It is clear that the future commercial exploitation of these species will need very careful management to ensure sustainability and avoid fishery over-depletion.

DNA microarray analysis was used to analyze the transcriptional profile of HCT116 colorectal cancer cells that were treated with 5-fluorouracil (5-FU) or oxaliplatin and selected for resistance to these agents. Bioinformatic analyses identified sets of genes that were constitutively dysregulated in drug-resistant cells and transiently altered following acute exposure of parental cells to drug. We propose that these genes may represent molecular signatures of sensitivity to 5-FU and oxaliplatin. Using real-time reverse transcription-PCR (RT-PCR), the robustness of our microarray data was shown with a strong overall concordance of expression trends for ≥82% (oxaliplatin) and ≥85% (5-FU) of a representative subset of genes. Furthermore, strong correlations between the microarray and real-time RT-PCR measurements of average fold changes in gene expression were observed for both the 5-FU (R2 ≥ 0.73) and oxaliplatin gene sets (R2 ≥ 0.63). Functional analysis of three genes identified in the microarray study [prostate-derived factor (PDF), calretinin, and spermidine/spermine N1-acetyl transferase (SSAT)] revealed their importance as novel regulators of cytotoxic drug response. These data show the power of this novel microarray-based approach to identify genes which may be important markers of response to treatment and/or targets for therapeutic intervention. (Cancer Res 2006; 66(5): 2765-77)

Hydraulic dredging that targets the bivalve Chamelea gallina in the northern and central Adriatic Sea (Italy) has been taking place for over 30 years. Seventy-three commercial dredgers harvest the resource within the sandy coastal area of the Ancona Maritime District (central Adriatic Sea). Despite this chronic disturbance, studies aimed at investigating the impacts of the fishery on the macrobenthic community of the area have never been carried out. To remedy this, sampling was accomplished within an area of the District from which hydraulic dredging was banned, within the framework of a balanced beyond-BACI (before/after, control/impact) experimental design. Data regarding seven groups of species were analysed separately by means of permutational multivariate analysis of variance. No impacts attributable to hydraulic dredging were found upon consideration of the entire sampled macrobenthic community, the Polychaeta, the Crustacea, detritivores, and suspensivores. In contrast, a sustained press impact of fishing was revealed for the Mollusca, and the bivalve Abra alba was found to be particularly susceptible. Abra alba was suggested as a possible impact indicator. A short-lived pulse impact on the predator and scavenger trophic guild was observed and was limited to the 1st sampling day after experimental hydraulic dredging.

Substratum un-acclimated juvenile queen scallops (Aequipecten opercularis) (

The abundance and diversity of meiofaunal bivalve species from four substrata (live maerl, dead maerl, gravel and sand) were investigated to assess the effects of habitat heterogeneity. Maerl grounds are unusual coastal habitats derived of non-geniculate coralline algae (Corallinaceae, Rhodophyta) and typically exhibit high benthic biodiversity, including a large number of molluscan species. In total 38 species of bivalves were recorded, with the greatest number found in dead maerl (29). These results were contrary to the findings of other authors who have shown dead maerl grounds to have a poorer fauna than live maerl beds. Significant differences were observed in the community structure of the substrata examined, with assemblages on sand being easily distinguishable from those on other substrata. Mysella bidentata was found to be an important species in dead maerl and gravel. In sand the tellinids Moerella pyg-maea and Angulus tennis were the most discriminatory species observed. Number of spec...

A study was made of the impacts on a benthic megafaunal community of a hydraulic blade dredge fishing for razor clams Ensis spp. within the Clyde Sea area. Damage caused to the target species and the discard collected by the dredge as well as the fauna dislodged by the dredge but left exposed at the surface of the seabed was quantified. The dredge contents and the dislodged fauna were dominated by the burrowing heart urchin Echinocardium cordatum, approximately 60–70% of which survived the fishing process intact. The next most dominant species, the target razor clam species Ensis siliqua and E. arcuatus as well as the common otter shell Lutraria lutraria, did not survive the fishing process as well as E. cordatum, with between 20 and 100% of individuals suffering severe damage in any one dredge haul. Additional experiments were conducted to quantify the reburial capacity of dredged fauna that was returned to the seabed as discard. Approximately 85% of razor clams retained the ability to rapidly rebury into both undredged and dredged sand, as did the majority of those heart urchins Echinocardium cordatum which did not suffer aerial exposure. Individual E. cordatum which were brought to surface in the dredge collecting cage were unable to successfully rebury within three hours of being returned to the seabed. These data were combined to produce a model of the fate of the burrowing megafauna dredged and dislodged in order to collect 10 kg of marketable razor clams.

Results obtained from circulating a questionnaire on seal/fisheries interaction around two groups of stakeholders (trawlermen and creel fishers) from the Scottish Clyde fishing fleet are presented. An overall return rate of 30% was achieved representing 664 man-years of traditional knowledge. Nowadays, most commercial fishing in the Clyde Sea area targets Norway lobsters (Nephrops norvegicus), using either towed (nephrops trawl) or static (baited creel) gear. Nephrops trawling generates a whitefish by-catch. All those respondents fishing within the confines of the Clyde Sea area reported experiencing seals interfering with their fishing activities. Both grey seals (Halichoerus grypus) and common, or harbour, seals (Phoca vitulina) occur locally but most respondents did not distinguish between them. The majority of trawlermen reported seals taking fishes from nets and damaging fishes. Only 9% of trawlermen, however, noted gear damage in spite of 91% reporting capturing seals (occasionally or rarely) in their gear. Seals caught in trawls were mostly retrieved dead (exact incidence unknown). Sixty-three percent of creelers who responded reported both damage to fishes and interference with creels. Seals may break into, or smash, creels to steal the bait and in so doing liberate catches. Contact with seals was not thought to taint fishing gear. Seals seemed to target cod (Gadus morhua) and hake (Merluccius merluccius) in trawls and seemed to select the larger individuals. Creel fishers highlighted damage to the bellies of fishes whilst trawlermen stressed damage to the tails. As much as 10% of the whitefish caught by trawlermen was unsaleable due to seal damage. Damage caused by seals was readily distinguishable from damage caused by other agents. ‘Rogue’ individual seals were not solely to blame. Typically, 9–12 seals (even sometimes as many as 25) might be encountered by any one fisher, especially when gear was being hauled. Half the trawlermen who participated regarded seals as being either a ‘considerable’ or ‘moderate’ threat to their livelihoods but 45% regarded them as a ‘minor’ or ‘non’-problem. Grey seal populations have undoubtedly increased considerably locally over the last 40 years. Eighty-six percent of trawlermen were in favour of some sort of seal cull (cf. 14% against), with some 45% of trawlermen in favour of halving seal numbers locally. Over 60% of creelers who responded were looking for even more stringent cut-backs in seal numbers, i.e. of more than 70%.

A short-term experiment to assess the ecological impact of a hydraulic blade dredge on a maerl community was carried out during November 2001 in the Clyde Sea area on the west coast of Scotland. A fluorescent sediment tracer was used to label dead maerl, which was then spread out on the surface of sediment to act as a proxy for living maerl. The fauna collected by the dredge was dominated by the bivalves Dosinia exoleta and Tapes rhomboides, which were found to be intact. The target razor clams Ensis spp. were caught in low numbers, which reflected the low abundance of this genus within the maerl habitat. The hydraulic dredge removed, dispersed and buried the fluorescent maerl at a rate of 5.2 kg m−2 and suspended a large cloud of sediment into the water column, which settled out and blanketed the seabed to a distance of at least 8 m either side of the dredge track. The likely ecological consequences of hydraulic dredging on maerl grounds are discussed, and a case is made for protecting all maerl grounds from hydraulic dredging and establishing them as reservoirs to allow for the recruitment of commercial bivalve populations at adjacent fished sites.

1. Maerl beds are carbonate sediments, built by a surface layer of slow-growing coralline algae, forming structurally fragile habitats. 2. They are of international conservation significance, often supporting a high biodiversity and abundant bivalve molluscs. 3. Experimental fishing for scallops (Pecten maximus) on French and UK grounds has shown that although large epifauna are often killed, many organisms escape harm as they burrow deeply or are small enough to pass through the dredges. 4. Bivalve dredging is currently one of the main threats to European maerl grounds as it reduces their biodiversity and structural complexity and can lead to long-term degradation of the habitat. 5. Protecting maerl grounds is of importance for fisheries since they provide structurally complex feeding areas for juvenile fish (e.g. Atlantic cod - Gadus morhua) and reserves of commercial brood stock (e.g. Ensis spp., P. maximus and Venus verrucosa). 6. We outline improved mechanisms to conserve these ancient and unique biogenic habitats.

Demersal fishing gear such as otter-trawls generate large amounts of unwanted by-catch. The Norway lobster ( Nephrops norvegicus ) is the most important shellfish resource in UK waters and although the fishing effort has increased considerably over past decades the ecosystem effects of this fishery have yet to be evaluated. This study provides the first assessment of the catch and discard composition from Nephrops trawls in the Clyde Sea area with particular emphasis on invertebrate discards. Nephrops constituted only between 14 and 23% of the total catch (volume); other invertebrates and fish accounted for the remainder of the catch. On an average, 9 kg of discards were produced per kilogram of Nephrops . The catch composition differed markedly between samples from the north and south Clyde Sea areas. Trawls from the south yielded a significantly higher biomass of Nephrops (30% cf. 4% in the north) and fish discards (55% cf. 36% in the north) whereas catches from the north contained more invertebrates (60% cf. 15% in the south). Crustaceans and echinoderms accounted for up to 83 and 73% of the discards, respectively. Samples from the north also contained a greater variety of invertebrate species (93 taxa cf. 51 taxa in the south). The differences between the two study areas are likely to be a reflection of differing bathymetries, hydrographic conditions and ground types in each area.

Generation of the amyloid peptide through proteolytic processing of the amyloid precursor protein by beta- and gamma-secretases is central to the etiology of Alzheimer's disease. The highly elusive beta-secretase was recently identified as a transmembrane aspartic proteinase, Asp2 (BACE). The Asp2 homolog Asp1 (BACE2/DRAP) has also been reported to exhibit beta-secretase cleavage of amyloid precursor protein. Most aspartic proteinases are generated as inactive proenzymes, requiring removal of the prodomain to generate active proteinase. Here we show that prodomain processing of Asp1 occurs between Leu(62) and Ala(63) and is autocatalytic. Asp1 cleaved a maltose-binding protein-Asp1 prodomain fusion protein and a synthetic peptide at this site. Mutation of one of the conserved catalytic aspartic acid residues in the active site of Asp1 to asparagine (D110N) abolished this cleavage. Mutation of P(1)' and P(2)' residues in the substrate to phenylalanine reduced cleavage at this site. Asp1 expressed in cells was the mature form, and prodomain processing occurred intramolecularly within the endoplasmic reticulum/early Golgi. Interestingly, a proportion of mature Asp1 was expressed on the cell surface. When full-length Asp1(D110N) was expressed in COS-7 cells, it was not processed, suggesting that no other proteinase can activate Asp1 in these cells.

Maerl beds are mixed sediments built by a surface layer of slow-growing, unattached coralline algae that are of international conservation significance because they create areas of high biodiversity. They are patchily distributed throughout Europe (to ∼30 m depth around the British Isles and to ∼120 m depth in the Mediterranean) and many are affected by towed demersal fishing. We report the effects of Newhaven scallop dredges on a previously unfished maerl bed compared with the effects on similar grounds that have been fished commercially in the Clyde Sea area, Scotland. Sediment cores were taken to assess the population density of live maerl thalli prior to scallop dredging on marked test and control plots. These plots were then monitored biannually over a four-year period. Live maerl thalli were sparsely distributed at the impacted site, and experimental dredging had no discernible effect on their numbers. The previously unfished ground had dense populations of live maerl and scallops (both Aequipecten opercularis and Pecten maximus). While counts of live maerl remained high on the control plot, scallop dredging led to a >70% reduction with no sign of recovery over the subsequent four years. The vulnerability of maerl and associated benthos (e.g., the delicate bivalve, Limaria hians) is discussed in relation to towed demersal fishing practices.

1. The case is made for recognition of the marine bivalve Limaria hians as a reef-forming species, which plays a key architectural role in certain benthic communities around the United Kingdom and Ireland. 2. This species uses byssal threads to construct nests that can coalesce to form reefs that cover hectares of seabed, contain multiple conspecifics and bind sediment. In so doing, L. hians modifies physical, chemical and biological processes at the sediment–water interface. 3. Such nests support a high diversity of associated organisms in coarse-grade sediments (19 species of algae and 265 species of invertebrates from six discrete nests in Loch Fyne are reported on), although the biological interactions between species both inside and outside this assemblage (e.g. predatory cod) are unknown. 4. Being insubstantial, labyrinthine structures situated on the sediment surface, Limaria nests are sensitive to mechanical impacts, such as those caused by moorings, hydraulic dredging for infaunal bivalves and scallop dredging. 5. At appropriate sites, the status of L. hians can contribute a useful indication of disturbance on coarse-grade sediments. Copyright © 2000 John Wiley & Sons, Ltd.

Rapido trawls are used to catch sole around the coast of Italy and to catch scallops in the northern Adriatic Sea but little is known about the environmental impact of this gear. Benthic surveys of a commercial scallop ground using a towed underwater television (UWTV) sledge revealed an expansive area of level, sandy sediment at 25 m characterized by high population densities of scallops (2·82 m −2 Aequipecten opercularis but fewer Pecten jacobaeus) together with ophiuroids, sponges, and the bivalve Atrina fragilis. Rapido trawls were filmed in action for the first time, providing information on the selectivity and efficiency of the gear together with its impact on the substratum and on the benthos. The trawls worked efficiently on smooth sand with ca. 44% catch rate for Pecten jacobaeus, of which 90% were >7 cm in shell height. Most organisms in the path of the trawl passed under or through the net; on average by-catch species only formed 19% of total catch by weight. Of the 78 taxa caught, lethal mechanical damage varied from 50% in soft-bodied organisms such as tunicates. A marked plot surveyed using towed UWTV before, then 1 and 15 h after fishing by Rapido trawl showed clear tracks of disturbed sediment along the trawl path where infaunal burrow openings had been erased. Abundant, motile organisms such as Aequipecten showed no change in abundance along these tracks although scavengers such as Inachus aggregated to feed on damaged organisms. There were significant decreases in the abundance of slow-moving/sessile benthos such as Pecten, Holothuria, and Atrina. Juvenile pectinids were abundant on the shells of Atrina. The introduction of a scheme of areas closed to trawling would protect highly susceptible organisms such as Atrina and enhance the chances of scallop recruitment to adjacent areas of commercial exploitation.

Dogwhelks, Nucella lapillus eat both barnacles and mussels, Mytilus edulis. However, mussels are dangerous prey because they can snare and immobilize dogwhelks with their byssi. Despite this danger, adult dogwhelks are common inside mussel hummocks or stacks found on mature mussel beds. The whelks live in debris-filled chambers within the hummocks, unsnared by byssi. Evidence is presented to show that this is a highly favourable microhabitat for dogwhelks. Condition index (CI) measurements showed that mean CI for “hummock” dogwhelks was 20.99 in early spring, 29.65 in midsummer and 34.86 in early winter. In comparison, CI values for dogwhelks from nearby barnacle zones were 20.13, 25.03 and 24.66 respectively. The summer and winter CI values of “hummock” dogwhelks were enhanced to a highly significant extent. Data are also presented to show that shore elevation or dogwhelk shell height (over the size range of animals studied) had no confounding effect on this result. Predicted flesh and shell mass values for a standard 25 mm high whelk showed that occupation of hummocks was associated with a thin-walled shell morphology, and that the shell mass became proportionately lower in summer and early winter. A feeding experiment showed that CI rises slowly, even in dogwhelks fed to satiation on mussels. Dogwhelks were taken from the barnacle zone in March 1997 and either fed to satiation on Mytilus or starved, whilst being held in seawater at ambient seawater temperature. The CI of fed dogwhelks rose from 19.7 to 27.4 in 3 months, while that of starved Nucella fell from 19.7 to 16.3. In the meantime, the CI of dogwhelks in situ in the barnacle zone had risen from 19.7 to 23.8. Hence, 3 months' satiation ration had led to a nett 3.6 unit rise in CI; starvation to a nett 7.5 unit fall. All of the changes in CI were due to changes in flesh mass; shell mass was stable. Since “hummock” dogwhelks collected in early winter have a CI value about 10.2 units greater than barnacle zone dogwhelks, this indicates that “hummock” dogwhelks are long-term inhabitants of this microhabitat.

Results are presented of a comparative study on seasonal variations in population density, population structure and reproductive bionomics of two species of offshore benthic oedicerotid amphipod, Westwoodilla caecula (from 35 m depth) and Monoculodes packardi (from 190 m) in Loch Fyne (Scotland). Observations on live coloration and behaviour of these species in laboratory aquaria are also included. Male W. caecula were, on average, smaller than females. In M. packardi (atypically among Oedicerotidae) the reverse was true. Population densities of both species, calculated from sledge net tows (1-mm mesh), fluctuated erratically over one year (1992). Ovigerous W, caecula were recorded virtually year-round, but were commonest from midsummer to early autumn. Ovigerous M. packardi were noted in spring and early autumn. Monoculodes packardi had a semi-annual life cycle, but the pattern for W. caecula was less clear. The two generations of M. packardi grew at broadly similar rates, presumably associated with the damped seasonal fluctuations in physical environmental factors at 190 m. Female W. caecula possibly moult eight or nine times, and may produce three successive broods in a lifetime (M. packardi may only produce two). A positive correlation was found between fecundity (stage I eggs) and body length in W. caecula but, although a similar trend was apparent in the data for M. packardi, relevant data were too few for significance to be achieved. Ovoid eggs increased in volume by ×2 from stage I-IV in W. caecula, or ×1·5 from stage I–III in M. packardi. Brood sizes were much smaller in W. caecula than in M. packardi, although apparent brood mortality was higher in the latter. There was no significant relationship between the proportion of ovigerous females in the populations of either species and seasonal variation in physical environmental factors considered (temperature, salinity, daylength).

Detailed catch and life history data for Perioculodes longimanus and Pontocrates arcticus, together with more limited comparable information on Synchelidium maculatum, are reported. Samples were taken year-round using a 0–5 mm mesh D-net towed over sand in the immediate sublittoral zone (-2 to -6 m Chart Datum) in Kames Bay, Great Cumbrae Island, Scotland. Estimated population densities of Perioculodes longimanus were highest in summer. The occurrence of Pontocrates arcticus was more erratic and S. maculatum occurred only in midsummer in very low numbers. The mean sizes of all population categories of Perioculodes longimanus were bigger in summer than in late autumn and winter. Female Perioculodes longimanus parasitized with the copepod Sphaeronella minuta were significantly smaller than the whole category ‘sexable females’. Adult female S. minuta (one per amphipod brood pouch infected) carried — 70–200 eggs per sac. In both Perioculodes longimanus and Pontocrates arcticus females were larger than males. In Synchelidium maculatum, by contrast, males and females were not different in size. Gravid females were present virtually year-round in Perioculodes longimanus and Pontocrates arcticus, with particularly high proportions of ovigerous females in midsummer and low proportions in midwinter. Both of these species had an annual life cycle with only one generation per year. Longevity was estimated at 15 months. The sex ratio nearly always showed substantial female dominance in all three species. Fecundity appeared to be related to body size but, due to egg losses during sample processing, data were too few for detailed analysis. The eggs of Perioculodes longimanus and Pontocrates arcticus were elliptical in shape, with winter eggs being smaller than summer eggs in Perioculodes longimanus, but larger in Pontocrates arcticus. The percentage of ovigerous females in the population was significantly correlated with a range of environmental factors tested, the highest correlation being with maximum weekly air temperature (for Perioculodes longimanus) and daylength (Pontocrates arcticus), although causative effects cannot be established since temperature/daylength factors were not independent variables

Thirteen species of Amphipoda have been recorded from the stomachs of plaice and 11 species from dabs, with Perioculodes longimanus the most notable prey oedicerotid in both flatfish species sampled from the shallow sublittoral zone (Angulus sp.). Polychaetes were more numerous in larger plaice. Sand gobies specialized on small crustaceans, taking 13 amphipod species inter alia (with P. longimanus again the most notable oedicerotid). Amphipod numbers in sand goby stomachs increased with the length of the fish. Neither dabs nor sand gobies consumed bivalve siphon tips and only rarely consumed polychaetes. Although amphipods formed only a minor part of the diet of plaice, at the population density known for this species in this bay, its depredations would still constitute an important selective agency governing patterns of activity in epibenthic oedicerotids.

Data are presented on the density of ten species of Amphipoda and two species of Isopoda from terrestrial to aquatic (freshwater through brackish water to marine) habitats, derived using a new modification of the displacement method involving batch testing of animals and subsequent Probit Analysis of data.Surprisingly few data are available in the literature concerning the densities of marine organisms. Extensive work on this topic was published some half a century ago by A.G. Lowndes. He reported widely on crabs and lobsters (Lowndes, 1943a), echinoderms (Lowndes, 1953) and fishes (Lowndes, 1955). In his paper to the Linnean Society (Lowndes, 1938a) he included data on some of the smaller freshwater Crustacea. Gross & Raymont (1942) have published on the specific gravity of the marine copepodCalanus finmarchicus.In espousing the displacement method for dealing with live individuals (Lowndes, 1938a,b, 1942, 1943b, 1955), he dismissed summarily earlier techniques that involved ascertaining whether killed or narcotized animals sank or floated in liquids of known density. While we recognize the limitations of the old methods, Lowndes’ displacement technique, although very accurate for individuals (he quoted figures to five decimal places), is very tedious to replicate [“elegant if somewhat exacting”, according to Hutchinson, 1967] and so reliance tends to be placed on figures obtained for very few individuals, typically only one or two. Even Lowndes himself was wary of attributing significance to the last two decimal places in his estimations, since individuals will vary in density according to sex, the contents of the gut etc. (Eyden, 1923; Lowndes, 1938b; but see Fox & Mitchell, 1953).

Ferritin crystals and calcium granules are reported from the ventral ceaca of Steleuthera ecoprophycea (Amphipoda: Stegocephalidae) collected from the Snake Pit hydrothermal vent, Mid-Atlantic Ridge (3520 m).In a series of earlier papers (Moore & Rainbow, 1984, 1989, 1992; Moore et al., 1994), the authors described the widespread occurrence of intracellular, octahedral crystals of ferritin in the ventral caeca of a range of stegocephalid amphipod species from the continental shelf epibenthos and oceanic plankton. The discovery at 3500 m of a new Steleuthera species (S. ecoprophycea), from a hydrothermal vent on the Mid-Atlantic Ridge was announced recently by Bellan-Santini & Thurston (1996), and a complete description is provided therein.Oceanic ridge sites are notable for their tectonic activity and the presence of a diversity of trace metals at high concentrations is to be expected in hydrothermal plumes emanating from such regions (German & Angel, 1995). The detoxification of accumulated trace metals in the ventral ceaca of stegocephalid amphipods from uncontaminated environments is now relatively well known (see above), so it was of interest to investigate whether a vent stegocephalid showed an atypical presence of trace metals in detoxified form in cells of the ventral caeca. The results following from an opportunity to investigate this are reported herein.Material was derived from a dive made by the submersible ‘Alvin’ at Snake Pit hydrothermal field, Mid-Atlantic Ridge (23°23′N 44°56′W), 3520 m, on 16 June 1993 (see Bellan-Santini & Thurston, 1996). Steleuthera ecoprophycea was preserved in 70% alcohol. Subsequently to dissection, the single pair of ventral caeca from each of the four damaged amphipods investigated were post-fixed in 4% glutaraldehyde. For electron microscopy and x-ray microanalysis in STEM mode, ventral caecal tissues were then dehydrated through 95% and absolute ethanol, cleared in propylene oxide, embedded in TAAB resin, sectioned at 0·5 μm (semi-thin sections) on a Reichert OmU2 ultramicrotome and examined without staining in a JEOL 100C electron microscope equipped with LINK system EDX energy dispersive x-ray microanalyser.

Dogwhelks, Nucella lapillus may be trapped by byssi of the mussel Mytilus edulis. Previous studies have suggested that such trapping contains elements of selectivity, deliberation and cooperativity. The following hypotheses were tested by field and laboratory studies: 1) that dogwhelks avoid high mussel population densities; 2) that mussels trap dogwhelks but ignore other gastropod species; 3) that mussels selectively attach to particular parts of the dogwhelk shell so that dogwhelks are overturned; 4) that dogwhelks can break free from byssal entrapment. The data collected supported hypotheses 1 and 4, but not hypotheses 2 and 3. It was found that mussels could snare dogwhelks and winkles, Littorina littorea, but that winkles could escape within minutes, while dogwhelks took several hours to break free. In both species, escape was achieved simply by sustained pulling of the threads until they snapped. Nucellas lapillus could escape from attachment by at least 18 byssi; Littorina littorea from at least 14. Permanent entrapment occurs when byssi attach from different directions (and different mussels). Dogwhelks avoid dense mussel cover, but exploit the margins of mussel beds, where they may break free of byssal attachment. Dogwhelks at the margins of such beds are significantly smaller than Nucellas lapillus living on barnacle-encrusted rock, and dogwhelks trapped within the matrix of mussel beds are smaller still. Dogwhelks at the margins of mussel beds had a mean of 5.15 ± 6.71 (S.D.) byssi attached to the shell; the value for N. lapillus within the mussel matrix was 24.00 ± 19.46. During field surveys a novel dogwhelk microhabitat, beneath mussel hummocks, was discovered. The area surrounding the dogwhelks was without mussel attachment to the rock. The mussel hummock was underlain by barnacle and mussel shell debris which retained moisture efficiently and in which large dogwhelks (not snared by byssi), often several beneath each hummock, were encountered. Overall it is clear that entrapment of N. lapillus by Mytilus edulis is a more stochastic, less selective process than claimed previously.

Field studies using fish-baited creels have confirmed that Carcinus maenas, Necora puber and Pagurus bernhardus (Crustacea: Decapoda), Buccinum undatum (Gastropoda) and Asterias rubens (Echinodermata) are prominent scavenging species in shallow waters in the Clyde Sea area. Capture rates of these species by creels baited with dead fish plus variously damaged C. maenas were examined in the field. The addition of substantially fractured C. maenas significantly reduced the capture of conspecifics, but significantly enhanced the capture of the taxonomically unrelated species A. rubens . The remaining crustacean taxa (of the above) were unaffected by this treatment. The magnitude of th response was related strongly to the extent to which C. maenas were damaged. The effects of hunger on these responses were tested in a laboratory experiment in which the responses of starved and fed batches of C. maenas were investigated. Starved crabs remained attracted to fish bait, despite the proximity of dead conspecifics. Conversely, crabs of the fed batch were significantly more reluctant to enter creels containing damaged conspecifics. The localized presence of odours emanating from dead conspecifics did not cause crabs to remain inactive in shelter. We conclude that taxonomic relatedness to bait, degree of carcass damage and hunger of the scavenger all interact in determining foraging decision-making even by so-called generalist scavengers.

Results of a comparative study on the distribution, growth and reproductive bionomics of two species of sand-dwelling oedicerotid amphipod, Pontocrates arenarius and P. Altamarinus are presented. Pontocrates arenarius is a littoral species with highest population densities between mean tide level (MTL) and low water springs (LWS) while P. altamarinus lives in the immediate sublittoral between LWS and -2 m Chart Datum. Both species are iteroparous, have female biased sex ratios, year-round breeding and life cycles largely based on two generations per year. The percentage of ovigerous females in the total population indicates breeding activity, and temporal changes in this percentage (arcsin transformed) have been tested for correlations against seasonal variation in five environmental factors (mean maximum weekly air temperature, mean minimum weekly air temperature, mean weekly sea temperature, day length, and mean weekly windspeed). Based on these analyses, differences in the timing of peak reproductive activity between these two species are interpreted as indicating the operation of different mortality agents, i.e. abiotic factors in the littoral P. arenarius and biotic effects (e.g. predation by fish) in P. altamarinus from the sublittoral.

The activity and life history of the cirolanid isopodNatatolana borealisLilljeborg has been studied using (primarily) fish-baited traps deployed at a deep-water station (190 m) in Loch Fyne, Scotland. A voracious scavenger, it burrows into soft mud, emerging to feed when suitable food odours are detected in the water. Isopods were attracted significantly to baitedvs. non-baited traps. Underwater video observations revealed that most animals were active in the vicinity of traps, that capture efficiency was low, but retention complete. Only traps on the sea-bed captured mancas or juveniles in any numbers. Any seasonal pattern in catch rate through the year was confounded by high variability. Only one (manca-)brooding female was ever caught in a trap (in April). It is assumed that brooding females desist from feeding. The sex ratio of isopods in most trap collections was thus significantly male dominated. Mancas were trapped during February to August. Growth rate was slowest in adults and was similar for males and females. The maximum growth rate occurred during autumn associated with the seasonal cycle in bottom water temperatures. Longevity was estimated (by following peaks in the size–frequency distributions with time) to bec. 2·5 years, with sexual maturity (based on oostegites/spurred appendix masculinae) achieved afterc. 19 months. Semelparity is suggested. A low incidence of an unnamed epicaridean parasite is reported from the Clyde population.Natatolana borealisalso carried peritrich ciliate epizoites on their antennae. Possible predators are swimming crabs and gadid fish, e.g. whiting and cod.

Orchomene nanus (Kroyer) was captured in funnel traps baited with crushed crabs [Carcinus maenas (L.)]. Monthly field samples were collected for population analysis over one year. Male Orchomene nanus can be distinguished most effectively from females and juveniles on the basis of the number of articles in antenna 2 flagellum. This flagellum becomes more elongate at each moult after sexual differentiation. The acquisition of calceoli reflects sexual maturation in males, as does a setose brood pouch in females. Analysis of the amalgamated size-frequency data for all seasons, allowed recognition of putative moult stages and calculation of moult-to-moult growth factors throughout the life of an individual (estimated to be 13 instars). Sexual differentiation occurred at instar 5 and maturity at instar 8. Males may live slightly longer than females. Females are iteroparous, producing three, perhaps four, broods. A two-generation life cycle involving a short-lived (7mo), fast growing summer generation and a longer-lived (12 months), slower growing generation that overwinters is hypothesized. Ovigerous females were present virtually year-round (none was recorded in October or January), resulting in domination of the population by juveniles for most of the year. Fecundity was related to female body size. Maximum clutch size was 26; with a lifetime potential fecundity calculated to be 27–52 eggs. Eggs doubled in volume during marsupial development. That hatchlings were under-represented in the collections could be due to sampler deficiencies (mesh size), or to behavioural differences, cf. adults. In most samples, the sex ratio was not significantly different from 1:1. However, a tendency toward female dominance was apparent overall (with the proviso that inaccuracies associated with recognition of the smallest males may have contributed to this finding).

The marine benthic isopod Natatolana borealis (Lilljeborg) displays attributes of a voracious omnivorous scavenger. It exhibited no preference for particular carrion types when given the choice between fish or crustacean tissue (variously treated) in situ. It was not attracted to live scampi (Nephrops narvegicus). Cannibalism of damaged or moulting individuals was observed frequently in the laboratory. Gut contents from field-collected animals frequently contained the remains of polychaetes and crustaeeans, though whether these had been ingested live is unknown. Natatolana borealis processes food in the manner of a ‘batch reactor’. It bolts food rapidly and unselectively, stores it in its extensible anterior hindgut, then takes a long time (weeks) to digest a single meal. It is inferred to have a high assimilation efficiency and can survive for long periods (months) without food. Sated isopods do not respond to food, but engage in a brief burst of post-prandial activity that would remove them fro...

Simultaneously deployed multiple-trap rigs were proven to function replicably at a shallow-water (5–6 m) study site. A standard (crushed) bait of whole crabs [Carcinus maenas (L.)] attracted significantly more Orchomene nanus than control (unbaited) traps. Traps were not inherently attractive. Crab bait was significantly more attractive than fish, or scampi. However, in a comparison between crushed representatives of three crab genera, no significant differences in the ability to attract Orchomene nanus were detected. Live Carcinus maenas attracted no Orchomene nanus. Crab limbs were as attractive as crab bodies minus limbs. Freshly dead crabs were more attractive than dead crabs that had been leached for 6 days. Fifty percent of Orchomene nanus survived 27 days in situ without extraneous food (although cannibalistic possibilities cannot be ruled out); a facility that would help overcome interludes of food shortage. All size-categories of Orchomene nanus were attracted to crab bait. Orchomene nanus is thus an unusual species: a diminutive, selective (and possibly obligate) scavenger specializing on high quality carrion.

“Orchestia” scutigerula Dana (Amphipoda: Talitridae) was found beneath supralittoral stones at Kanin Point, S. Georgia. Microhabitat temperatures recorded over 6 summer weeks varied widely (hourly, diurnally, weekly), especially under stones highest upshore. In air, “O.” scutigerula tolerated temperatures between −2 and 19 °C. Temperatures between 19 and 28 °C were survivable only in fully saturated air. In water, a temperature of 19 °C was tolerated for 6 h. The locomotory behaviour (walking) of amphipods for 3 h underwater was the same in distilled water as seawater. After 6 h in distilled water, amphipods exhibited distress, and after 7 h most were incapable of walking. “O.” scutigerula is a strong hyper/hypo-osmoregulator during short-term exposure to a wide range of salinities. All individuals tested survived any combination of salinity and temperature between 5 and 34‰ and 2 and 12 °C. Amphipods chose, (a) shaded conditions both in air or in water, (b) moist to dry gravel, and (c) moist gravel to moist sand. They did not burrow into moist sand, even though markedly thigmokinetic. In uniform, featureless containers amphipods were quiescent during the day, clumping together. At night such clumps dispersed and exploratory activity increased. Swimming was never observed, and when out of water these talitrids hopped rarely. Tussock grass and macroalgal debris dominated their gut contents in situ, with terrestrial plant debris increasing in prominence in amphipods from higher upshore. Feeding trials revealed high consumption of rotting tussock grass debris and green algae (Ulothrix, Ulva). Soft materials were consumed preferentially. Rate of passage of food through the gut was very variable, both within and between individuals. Underwater, “O.” scutigerula fed at half the rate in air. Food preferences of individuals sometimes switched between equally available foods over time. Fecundity is linearly related to female body length. Eggs more than double in volume during development.

The scavenging lysianassoid Orchomene nanus virtually monopolized catches of amphipods taken in baited traps (using crushed shore crabs Carcinus maenas as bait) deployed in shallow water (5–6 m). Only traps deployed overnight attracted O. nanus . Activity was not associated with any particular time of night. Differences in sub-surface temperature correlated significantly with variation in nightly catch rate (data for May), but this may not reflect a direct causal relationship. A lunar cycle of activity, however, was implicated in May. Trap retention efficiency proved to be high. There was an exponential decline in catch rate with trap elevation above the sea bed. Seasonal variation in catch rate was apparent, with highest catches in late autumn, correlating significantly with seasonal variation in water temperature. Neither the seasonal variation in the duration of darkness, nor the position of the sample day in the lunar cycle influenced seasonal catches significantly.